The Malbim says that Bnei Yisroel are higher than Tevah (nature) and even the most powerful: witchcraft and real black magic is nothing by them, since they have Hashem. Bilam complained to his donkey: “You made a joke out of me”. This is exactly the Lashon that Hashem used (He made a joke of Mitzrayim) and this is exactly what every Yid should do when he works on Bitachon, i.e., to make fun of Tevah (nature) e.g., the doctor’s negative reports, Rachmana Litzlan, or tremendous Chovos (debts), or difficult relationships, etc.
The Chovos Halvavos at the beginning of Shaar HaBitachon brings a Passuk referring to the Ma'aseh Eigel, which is compared to a picture of an ox eating grass, i.e., a big joke. The story of Bilam is a mystery, full of the secrets of the Torah. But in general, we have a message of how the most powerful human who had Kochos HaTum'ah like no one else (he could even fly in the air) and his blessings and curses always came true... here the Torah makes a joke of him, with a donkey opening its mouth and putting him in his place.
